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901.
Fernández-Acero FJ Jorge I Calvo E Vallejo I Carbú M Camafeita E Garrido C López JA Jorrin J Cantoral JM 《Archives of microbiology》2007,187(3):207-215
Botrytis cinerea is a phytopathogenic fungus causing disease in a substantial number of economically important crops. In an attempt to identify putative fungal virulence factors, the two-dimensional gel electrophoresis (2-DE) protein profile
from two B. cinerea strains differing in virulence and toxin production were compared. Protein extracts from fungal mycelium obtained by tissue
homogenization were analyzed. The mycelial 2-DE protein profile revealed the existence of qualitative and quantitative differences
between the analyzed strains. The lack of genomic data from B. cinerea required the use of peptide fragmentation data from MALDI-TOF/TOF and ESI ion trap for protein identification, resulting
in the identification of 27 protein spots. A significant number of spots were identified as malate dehydrogenase (MDH) and
glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The different expression patterns revealed by some of the identified proteins
could be ascribed to differences in virulence between strains. Our results indicate that proteomic analysis are becoming an
important tool to be used as a starting point for identifying new pathogenicity factors, therapeutic targets and for basic
research on this plant pathogen in the postgenomic era. 相似文献
902.
Iron scarcity is one of the nutrition limitations that the Gram-positive infectious pathogens Streptococcus pneumoniae encounter in the human host. To guarantee sufficient iron supply, the ATP binding cassette (ABC) transporter Pia is employed to uptake iron chelated by hydroxamate siderophore, via the membrane-anchored substrate-binding protein PiaA. The high affinity towards ferrichrome enables PiaA to capture iron at a very low concentration in the host. We presented here the crystal structures of PiaA in both apo and ferrichrome-complexed forms at 2.7 and 2.1 Å resolution, respectively. Similar to other class III substrate binding proteins, PiaA is composed of an N-terminal and a C-terminal domain bridged by an α-helix. At the inter-domain cleft, a molecule of ferrichrome is stabilized by a number of highly conserved residues. Upon ferrichrome binding, two highly flexible segments at the entrance of the cleft undergo significant conformational changes, indicating their contribution to the binding and/or release of ferrichrome. Superposition to the structure of Escherichia coli ABC transporter BtuF enabled us to define two conserved residues: Glu119 and Glu262, which were proposed to form salt bridges with two arginines of the permease subunits. Further structure-based sequence alignment revealed that the ferrichrome binding pattern is highly conserved in a series of PiaA homologs encoded by both Gram-positive and negative bacteria, which were predicted to be sensitive to albomycin, a sideromycin antibiotic derived from ferrichrome. 相似文献
903.
Riccardo Montioli Carlotta Zamparelli Carla Borri Voltattorni Barbara Cellini 《The protein journal》2017,36(3):174-185
Human ornithine δ-aminotransferase (hOAT) (EC 2.6.1.13) is a mitochondrial pyridoxal 5′-phosphate (PLP)-dependent aminotransferase whose deficit is associated with gyrate atrophy, a rare autosomal recessive disorder causing progressive blindness and chorioretinal degeneration. Here, both the apo- and holo-form of recombinant hOAT were characterized by means of spectroscopic, kinetic, chromatographic and computational techniques. The results indicate that apo and holo-hOAT (a) show a similar tertiary structure, even if apo displays a more pronounced exposure of hydrophobic patches, (b) exhibit a tetrameric structure with a tetramer-dimer equilibrium dissociation constant about fivefold higher for the apoform with respect to the holoform, and (c) have apparent Tm values of 46 and 67?°C, respectively. Moreover, unlike holo-hOAT, apo-hOAT is prone to unfolding and aggregation under physiological conditions. We also identified Arg217 as an important hot-spot at the dimer–dimer interface of hOAT and demonstrated that the artificial dimeric variant R217A exhibits spectroscopic properties, Tm values and catalytic features similar to those of the tetrameric species. This finding indicates that the catalytic unit of hOAT is the dimer. However, under physiological conditions the apo-tetramer is slightly less prone to unfolding and aggregation than the apo-dimer. The possible implications of the data for the intracellular stability and regulation of hOAT are discussed. 相似文献
904.
Moose summer and winter diets along a large scale gradient of forage availability in southern Norway
Studies on dietary functional responses in large herbivores are traditionally conducted by following individual animals. The
method is very time-consuming, and hence, typically provides only a narrow array of forage species compositions. Here we use
a range level approach to look at moose (Alces alces) selectivity for and utilization of forage species in relation to availability in both summer and winter. We compare 12 Norwegian
ranges representing a large scale gradient in plant communities. The most important forage species in the diet were birches
(Betula spp., comprising 43% of all trees browsed in summer and 27% in winter), rowan (Sorbus aucuparia, 25% of trees browsed in summer, 37% in winter), and bilberry (Vaccinum myrtillus, 42% of herbaceous epidermal fragments in summer feces). Selectivity for birches was positively related to its availability
and negatively related to availability of rowan, Salix spp., and aspen (Populus tremula) together (all more selected for than birches). Multiple regression models including availability of several forage species
were thus superior to single-species models in explaining the diet content of main forage plants. Selectivity for birches
was also stronger in summer than in winter, while the opposite pattern was found for rowan. The finding is relevant for our
evaluation of the quality of summer and winter ranges, and hence, their relative influence on population productivity. Our
study underlines the need to incorporate species composition of available forage when quantifying dietary functional responses
in selective herbivores such as moose. Furthermore, care should be taken when extrapolating data on moose diet across ranges
or seasons. 相似文献
905.
Leila M. Porter Sarah M. Sterr Paul A. Garber 《International journal of primatology》2007,28(5):1035-1058
We studied the diet, habitat use, and ranging behavior of 1 group of Callimico goeldii (callimicos) over 12 mo in northwestern Bolivia. The group’s diet was comprised of fungi (39%), fruits (31%), arthropods
(14%), exudates (14%), and other matter (2%). Callimicos concentrated their ranging activities in secondary forest (50%),
primary forest with dense understory (30%), and bamboo (17%) habitats. The group’s total home range was 114 ha; on average
they used 38.4 ha/ mo and had a day range of 925 m. Monthly average day ranges—but not monthly home ranges—increased as frugivory
declined, suggesting that subjects foraged on fungi and exudates by rechecking resources within a core area, making their
day ranges longer than during months when they concentrated on fruit resources. The callimicos formed polyspecific associations
with tamarins (Saguinus labiatus and S. fuscicollis) during 81% of observations. Day ranges increased in months with higher association rates which appears to result from the
callimicos using a broader set of habitats when with tamarins than when alone. The ranging pattern of callimicos appears to
be influenced primarily by 3 factors: their seasonal shift in diet requires that they forage in a variety of habitats across
the year; their depletion of resources causes them to shift their core area over time; and their lack of territorial behavior
eliminates the need to patrol boundaries as part of their daily movement. As a result, callimicos differ from many other callitrichids
in their low ratio of day range length to home range size. 相似文献
906.
Roxane M Barthélémy Anne Chenuil Samuel Blanquart Jean-Paul Casanova Eric Faure 《BMC evolutionary biology》2007,7(1):146
Background
Chaetognaths, or arrow worms, are small marine, bilaterally symmetrical metazoans. The objective of this study was to analyse ribosomal protein (RP) coding sequences from a published collection of expressed sequence tags (ESTs) from a chaetognath (Spadella cephaloptera) and to use them in phylogenetic studies. 相似文献907.
Ho Cheng Koc Jing Xiao Weiwei Liu Yong Li Guokai Chen 《International journal of biological sciences》2022,18(12):4768
The pandemic of COVID-19 is the biggest public health crisis in 21st Century. Besides the acute symptoms after infection, patients and society are also being challenged by the long-term health complications associated with COVID-19, commonly known as long COVID. While health professionals work hard to find proper treatments, large amount of knowledge has been accumulated in recent years. In order to deal with long COVID efficiently, it is important for people to keep up with current progresses and take proactive actions on long COVID. For this purpose, this review will first introduce the general background of long COVID, and then discuss its risk factors, diagnostic indicators and management strategies. This review will serve as a useful resource for people to understand and prepare for long COVID that will be with us in the foreseeable future. 相似文献
908.
At the beginning of the twentieth century, the biologist Joseph Grinnell made a distinction between science and sentiment for producing fact-based generalizations on how to conserve biodiversity. We are inspired by Grinnellian science, which successfully produced a century-long impact on studying and conserving biodiversity that runs orthogonal to some familiar philosophical distinctions such as fact versus value, emotion versus reason and basic versus applied science. According to Grinnell, unlike sentiment-based generalizations, a fact-based generalization traces its diverse commitments and thus becomes tractable for its audience. We argue that foregrounding tractability better explains Grinnell’s practice in the context of his time as well as in the context of current discourse among scientists over the political “biases” of biodiversity research and its problem of “reproducibility.” 相似文献
909.
THE polysaccharides obtained from some basidiomycetes, Pleurotus ostreatus (Jacq. ex Fr.) Quel.1, Flammulina velutipes (Curt, ex Fr.) Sing.2, Lentinus edodes (Berk.) Sing.2–4, Polia cocos, Wolf (Bukuryo)5 and Schizophyllum commune Fr.7, strongly inhibit the growth of sarcoma 180 and their anti-tumour activity is host-mediated8,9. 相似文献
910.
Alexey V. Morozov Tatiana M. Astakhova David G. Garbuz George S. Krasnov Natalia V. Bobkova Olga G. Zatsepina Vadim L. Karpov Michail B. Evgen’ev 《Cell stress & chaperones》2017,22(5):687-697
The heat shock protein 70 (Hsp70, human HSPA1A) plays indispensable roles in cellular stress responses and protein quality control (PQC). In the framework of PQC, it cooperates with the ubiquitin-proteasome system (UPS) to clear damaged and dysfunctional proteins in the cell. Moreover, Hsp70 itself is rapidly degraded following the recovery from stress. It was demonstrated that its fast turnover is mediated via ubiquitination and subsequent degradation by the 26S proteasome. At the same time, the effect of Hsp70 on the functional state of proteasomes has been insufficiently investigated. Here, we characterized the direct effect of recombinant Hsp70 on the activity of 20S and 26S proteasomes and studied Hsp70 degradation by the 20S proteasome in vitro. We have shown that the activity of purified 20S proteasomes is decreased following incubation with recombinant human Hsp70. On the other hand, high concentrations of Hsp70 activated 26S proteasomes. Finally, we obtained evidence that in addition to previously reported ubiquitin-dependent degradation, Hsp70 could be cleaved independent of ubiquitination by the 20S proteasome. The results obtained reveal novel aspects of the interplay between Hsp70 and proteasomes. 相似文献